1. Field of Invention
The present invention relates generally to electronic mail management, and, in particular, to collaborative junk filtering of electronic mail at a service provider.
2. Description of Background
Present electronic mail services offered by Internet service providers (ISPs) are typically protected, to a certain level, from being attacked by vicious and malicious viruses, Trojan horses etc. However, only a very limited extent of protection is presently provided from meaningless spam and propositions from nonexistent enterprises and people who are trying to take advantage of electronic mail subscribers and/or infect their mailboxes. These protection mechanisms include virus detection in firewalls, virus scans on personal computers, and junk mail filters on local electronic mail clients. Another example of an approach to assist in detecting false identities in electronic mail is DomainKeys Identified Mail (DKIM), which allows electronic mail senders to “sign” each electronic mail message to verify that it comes from their domain. If the receiving domain handles an electronic mail message that does not contain the signature, it can raise a red flag to warn the recipient that the message might be a fake. These various protection and alerting schemes have a common objective of reducing the danger of being infected by malicious viruses, as well as reducing the amount of junk mail; nevertheless, electronic mail box users world-wide are being overloaded with unwanted junk mail every day.
It is not only electronic mail messages composed by fictive users at various domains, but also actual users at real domains, which jam electronic mail boxes with spam and must be screened by a user before it can be categorized as junk. For example, legitimate organizations can generate a large volume of electronic mail but be non-responsive to requests to “unsubscribe” users from the associated mailing lists. Some users may desire the electronic mail messages, while others find them a nuisance. Since categorizing these types of messages as junk or not junk is a matter of individual preference, ISPs cannot apply wide-scale filtering to eliminate the messages. Many users that are connected by some common characteristic (such as a family, a profession, a religion, a political view, and the like) may have common views as to what types of messages they consider to be junk. Therefore, it would be beneficial to develop a system that applies a collaborative community approach to reduce junk mail. Such an approach would be implemented at a higher-level service provider, e.g., at an ISP, to provide many users access and prevent unsecured junk mail from reaching client systems of the individual users. Accordingly, there is a need in the art for collaborative filtering of junk electronic mail.